# US 2010/0163757 A1 · Pulse Modifier with Adjustable Etendue > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0163757 A1 - Document ID: US20100163757A1 - Status: Published application - Kind: A1 - Application number: 12/615,328 - Filed: 2009-11-10 - Published: 2010-07-01 - Earliest claimed: 2008-12-31 - Assignees: ASML Holding N.V.; ASML Netherlands B.V. - Inventors: Adel Joobeur; Oscar Franciscue Jozephus Noordman; Paul Van der veen; Arun Mahadevan Venkataraman - Web page: https://patentgrep.com/patent/US20100163757A1 ## CPC - G03F 7/70583: {Speckle reduction, e.g. coherence control or amplitude/wavefront splitting} - G02B 27/144: {using partially transparent surfaces without spectral selectivity (G02B27/147 takes precedence)} - G02B 27/145: {having sequential partially reflecting surfaces} - H01S 3/0057: {Temporal shaping, e.g. pulse compression, frequency chirping (soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108)} - G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL ## Abstract A beam modifying unit increases both temporal pulse length and Etendue of an illumination beam. The pulse modifying unit receives an input pulse of radiation and emits one or more corresponding output pulses of radiation. A beam splitter divides the incoming pulse into a first and a second pulse portion, and directs the first pulse portion along a second optical path and the second portion along a first optical path as a portion of an output beam. The second optical path includes a divergence optical element. A first and a second mirror, each with a radius of curvature, are disposed facing each other with a predetermined separation, and receive the second pulse portion to redirect the second portion, such that the optical path of the second portion through the pulse modifier is longer than that of the first portion, and the separation is less than radius of curvature. ## Claims ### Claim 1 A system, comprising: first and second curved reflecting devices; a beam splitter; and a divergence optical element, wherein the beam splitter is configured to reflect a first portion of a beam towards the divergence optical element, which begins a cycle during which the beam travels through the system, and to transmit a second portion of the beam to generate at least a portion of an output beam, wherein during the cycle the divergence optical element directs the first portion of the beam along a beam path between the first and second reflecting devices, such that the first portion of the beam traverses between the first and second reflecting devices more than once, wherein the cycle ends after traversal between the first and second reflecting devices, such that a first part of the first portion of the beam is reflected by the beam splitter and exits the system to generate another portion of the output beam and a second part of the first portion of the beam is transmitted through the beam splitter to repeat the cycle. ### Claim 2 (depends on 1) The system of claim 1, wherein: a first segment of the cycle comprises a beam path from the first reflecting device to the second reflecting device; a second segment of the cycle comprises a beam path from the second curved reflecting device to the first curved reflecting device; a third segment of the cycle comprises a beam path from the first curved reflecting device to the second curved reflecting device; and a fourth segment of the cycle comprises a beam path from the second curved reflecting device to the beam splitter. ### Claim 3 (depends on 1) The system of claim 1, wherein the first and second curved reflecting devices comprise a confocal mirror. ### Claim 4 (depends on 1) The system of claim 1, wherein the divergence optical element comprises an optical wedge. ### Claim 5 (depends on 1) The system of claim 1, wherein the divergence optical element is configured to substantially reduce or eliminate speckle in the output beam. ### Claim 6 (depends on 1) The system of claim 1, wherein the divergence optical element is configured to increase divergence of the first portion of the beam without decreasing beam size to increase an Etendue of the output beam. ### Claim 7 (depends on 1) The system of claim 1, wherein the first and second curved reflecting devices are configured to delay and reimage the first portion of the beam at the beam splitter. ### Claim 8 (depends on 1) The system of claim 1, wherein the divergence optical element is configured to increase divergence of the first portion of the beam without decreasing beam size to increase a temporal pulse length of the first portion of the beam. ### Claim 9 (depends on 1) The system of claim 1, wherein the divergence optical element is configured to change the divergence of the first portion of the beam through change of an angle of the divergence optical element with respect to the beam splitter and the first and second curved reflecting devices. ### Claim 10 (depends on 1) The system of claim 1, wherein the divergence of the first portion of the beam changes after each cycle of the beam path through subsequent passes through the divergence optical element. ### Claim 11 A system, comprising: first and second curved reflecting devices; a first and second beam splitter; and a first and second divergence optical element, wherein the first beam splitter is configured to reflect a first portion of a beam towards the first divergence optical element, which begins a first cycle during which the beam travels through the system, and to transmit a second portion of the beam towards the second beam splitter, wherein the second beam splitter is configured to reflect a third portion of a beam towards the second divergence optical element, which begins a second cycle during which the beam travels through the system, and to transmit a fourth portion of the beam to generate at least a portion of the output beam, wherein during the first cycle the first divergence optical element directs the first portion of the beam along a first beam path between the first and second reflecting devices, such that the first portion of the beam traverses between the first and second reflecting devices more than once, wherein during the second cycle the second divergence optical element directs the third portion of the beam along a second beam path between the first and second reflecting devices, such that the first portion of the beam traverses between the first and second reflecting devices more than once, wherein the first cycle ends after traversal between the first and second reflecting devices, such that a first part of the first portion of the beam is reflected by the first beam splitter towards the second beam splitter and a second part of the first portion of the beam is transmitted through the first beam splitter to repeat the first cycle, and wherein the second cycle ends after traversal between the first and second reflecting devices, such that a first part of the third portion of the beam is reflected by the second beam splitter and exits the system to generate another portion of the output beam and a second part of the third portion of the beam is transmitted through the second beam splitter to repeat the second cycle. ### Claim 12 A system, comprising: first and second curved reflecting devices; a beam splitter; and a parallel plate optical element, wherein the beam splitter is configured to reflect a first portion of a beam towards the parallel plate optical element, which begins a cycle during which the beam travels through the system, and to transmit a second portion of the beam to generate at least a portion of an output beam, wherein during the cycle the parallel plate optical element directs the first portion of the beam along a beam path between the first and second reflecting devices, such that the first portion of the beam traverses between the first and second reflecting devices more than once, wherein the cycle ends after traversal between the first and second reflecting devices, such that a first part of the first portion of the beam is reflected by the beam splitter and exits the system to generate another portion of the output beam and a second part of the first portion of the beam is transmitted through the beam splitter to repeat the cycle. ### Claim 13 (depends on 12) The system of claim 12, wherein: a first segment of the cycle comprises a beam path from the first reflecting device to the second reflecting device; a second segment of the cycle comprises a beam path from the second curved reflecting device to the first curved reflecting device; a third segment of the cycle comprises a beam path from the first curved reflecting device to the second curved reflecting device; and a fourth segment of the cycle comprises a beam path from the second curved reflecting device to the beam splitter. ### Claim 14 (depends on 12) The system of claim 12, wherein the first and second curved reflecting devices comprise a confocal mirror. ### Claim 15 (depends on 12) The system of claim 12, wherein the parallel plate optical element is configured to increase beam size of the first portion of the beam while maintaining a constant divergence to increase an Etendue of the output beam. ### Claim 16 A method, comprising: splitting a beam of radiation into a first and a second portion; increasing a divergence of the first portion of the beam; reflecting the first portion of the beam, such that the optical path of the first portion is longer than an optical path of the second portion; and recombining the first portion of the beam with the second portion. ### Claim 17 (depends on 16) The method of claim 16, further comprising varying an amount of the divergence of the first portion of the input beam. ### Claim 18 (depends on 16) The method of claim 16, further comprising substantially reducing or eliminating speckle in the output beam. ### Claim 19 (depends on 16) The method of claim 16, further comprising increasing the divergence of the beam without decreasing beam size to increase an Etendue of the beam. ### Claim 20 (depends on 16) The method of claim 16, further comprising increasing the divergence of the beam without decreasing beam size to increase a temporal pulse length of the beam.